Refrigerator and control method for the same

ABSTRACT

A refrigerator includes a plurality of storage compartments, a plurality of cooling units to cool the plurality of storage compartments, a temperature sensing unit to sense temperatures of the plurality of storage compartments, a drive unit to drive the plurality of cooling units, and a controller to control the drive unit to drive the cooling unit that satisfies a predetermined driving condition. If at least one cooling unit among the plurality of cooling units is being driven, the controller delays driving the other cooling unit even if the other cooling unit satisfies the driving condition. The refrigerator minimizes simultaneous driving a plurality of compressors, which may prevent generation of noise and vibration, as well as excessive power consumption, due to driving the plurality of compressors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/935,742, filed on Jul. 5, 2013 in the U.S. Patent and TrademarkOffice, which claims the priority benefit of Korean Patent ApplicationNo. 10-2012-0075289, filed on Jul. 10, 2012 and Korean PatentApplication No. 10-2013-0057687, filed on May 22, 2013 in the KoreanIntellectual Property Office, the disclosures of which are incorporatedherein by reference.

BACKGROUND

1. Field

The following description relates to a refrigerator using a plurality ofcompressors, and a control method for the same.

2. Description of the Related Art

A refrigerator is an apparatus that keeps food and beverages, forexample, fresh for a long time.

A refrigerator has a plurality of storage compartments including afreezing compartment in which food is kept below a freezing temperature,and a refrigerating compartment in which food is kept at a temperatureslightly above freezing. In addition, a variable temperature chamber forlong time storage of fresh goods, such as vegetables and fish, forexample, may be provided.

Such a refrigerator keeps a storage compartment at a predeterminedtarget temperature via an iterative implementation of a refrigerationcycle consisting of compression, condensation, expansion, andevaporation of a refrigerant. That is, the refrigerator supplies air,cooled by an evaporator provided for each storage compartment, into eachstorage compartment based on a target temperature of the storagecompartment, thereby keeping the storage compartment at the targettemperature.

Conventional refrigerators keep a freezing compartment and arefrigerating compartment at respective target temperatures using asingle evaporator and do not provide appropriate cooling environments.

In recent years, a refrigerator in which evaporators are respectivelyprovided at a freezing compartment and a refrigerating compartment hasbeen developed. The refrigerator includes a switching valve to control aflow path of refrigerant to be supplied to the evaporator provided atthe freezing compartment or the refrigerating compartment, such that therefrigerant, condensed through a compressor and a condenser, is suppliedto the evaporator provided at the freezing compartment or therefrigerating compartment according to temperatures of the freezingcompartment and the refrigerating compartment.

However, the aforementioned refrigerator adopts a single compressor anda single condenser, causing difficulty in simultaneously cooling thefreezing compartment and the refrigerating compartment, which differgreatly in target temperature. Moreover, due to addition of a variabletemperature chamber for storage of fresh goods, such as vegetables,fish, or meat, and a considerable increase in capacities of the freezingcompartment and the refrigerating compartment, insufficient compressorcapacity has become a major issue.

SUMMARY

Therefore, it is an aspect of the present disclosure to provide arefrigerator using a plurality of compressors and a control method forthe same.

Additional aspects of the invention will be set forth in part in thedescription which follows and, in part, will be obvious from thedescription, or may be learned by practice of the invention.

In accordance with an aspect of the present disclosure, a refrigeratorincludes a plurality of storage compartments, a plurality of coolingunits to cool the plurality of storage compartments, a temperaturesensing unit to sense temperatures of the plurality of storagecompartments, a drive unit to drive the plurality of cooling units, anda controller to control the drive unit to drive the cooling unit thatsatisfies a predetermined driving requirement, wherein if at least onecooling unit among the plurality of cooling units is being driven, thecontroller delays driving the other cooling unit even if the othercooling unit satisfies the driving requirement. The driving requirementmay include the temperature of the storage compartment reaches orexceeds a predetermined upper limit temperature.

If the at least one cooling unit is being driven, the controller maydrive the other cooling unit if the other cooling unit satisfies apredetermined delayed driving requirement.

The delayed driving requirement may include the temperature of thestorage compartment that is cooled by the other cooling unit reaches orexceeds a predetermined delay temperature.

The delayed driving requirement may include a predetermined delay timehas passed after the at least one cooling unit is driven.

The controller may reduce driving rates of the at least one cooling unitand the other cooling unit if the at least one cooling unit and theother cooling unit are driven simultaneously.

The controller may stop driving the at least one cooling unit if theother cooling unit satisfies the delayed driving requirement.

The controller may drive the other cooling unit if the at least onecooling unit satisfies a predetermined driving stop requirement, eventhough the other cooling unit does not satisfy the delayed drivingrequirement.

The driving stop requirement may include the temperature of the storagecompartment that is cooled by the at least one cooling unit reaches orfalls below a predetermined lower limit temperature.

In accordance with an aspect of the present disclosure, a control methodfor a refrigerator including a plurality of storage compartments, aplurality of cooling units to cool the plurality of storagecompartments, and a temperature sensing unit to sense temperatures ofthe plurality of storage compartments, includes driving at least onecooling unit among the plurality of cooling units that satisfies apredetermined driving requirement, and delaying driving the othercooling unit if the at least one cooling unit is being driven, eventhrough the other cooling unit satisfies the driving requirement.

Delaying driving the other cooling unit may include driving the othercooling unit if the other cooling unit satisfies a predetermined delayeddriving requirement.

The control method may further include, if the other cooling unit isbeing driven, driving the at least one cooling unit as well as the othercooling unit by reducing driving rates of the at least one cooling unitand the other cooling unit.

The control method may further include stopping driving the at least onecooling unit if the other cooling unit is driven.

Driving the at least one cooling unit may include the cooling unit thatcools any one of the plurality of storage compartments, the temperatureof which reaches or exceeds a predetermined upper limit temperature.

Driving the other cooling unit may include driving the other coolingunit if the temperature of the storage compartment that is cooled by theother cooling unit reaches or exceeds a predetermined delay temperature.

In accordance with an aspect of the present disclosure, a refrigeratorincludes a refrigerating compartment, a freezing compartment spatiallyseparated from the refrigerating compartment, a first cooling unit tocool the refrigerating compartment, a second cooling unit to cool thefreezing compartment, a temperature sensing unit to sense temperaturesof the refrigerating compartment and the freezing compartment, a driveunit to drive the first cooling unit and the second cooling unit, and acontroller to control the drive unit to drive the first cooling unit orthe second cooling unit that satisfies a driving requirement, wherein ifat least one of the first cooling unit and the second cooling unit isbeing driven, the controller delaying driving the other cooling uniteven if the other cooling unit satisfies the driving requirement.

The driving requirement may include the temperature of the storagecompartment reaches or exceeds an upper limit temperature.

If the at least one cooling unit is being driven, the controller maydrive the other cooling unit if the other cooling unit satisfies apredetermined delayed driving requirement.

The delayed driving requirement may include the temperature of thestorage compartment that is cooled by the other cooling unit reaches orexceeds a predetermined delay temperature.

The delayed driving requirement may include a predetermined delay timehas passed after the at least one cooling unit is driven.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent andmore readily appreciated from the following description of theembodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a front view illustrating a refrigerator according to anembodiment of the present disclosure;

FIG. 2 is a view illustrating a cooling unit according to an embodimentof the present disclosure;

FIG. 3 is a block diagram illustrating a refrigerator according to anembodiment of the present disclosure;

FIG. 4 is a view showing temperature variation of a first storagecompartment and a second storage compartment in a normal operation modeof the refrigerator according to an embodiment of the presentdisclosure;

FIG. 5 is a flowchart illustrating a control method for the refrigeratoraccording to an embodiment of the present disclosure;

FIG. 6 is a flowchart illustrating the control method in an initialoperation mode of the refrigerator according to an embodiment of thepresent disclosure;

FIG. 7 is a flowchart illustrating the control method upon driving afirst cooling unit of the refrigerator according to an embodiment of thepresent disclosure; and

FIG. 8 is a flowchart illustrating the control method upon driving asecond cooling unit of the refrigerator according to an embodiment ofthe present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout.

FIG. 1 is a front view illustrating a refrigerator 100 according to anembodiment of the present disclosure, FIG. 2 is a view illustrating acooling unit 200 according to an embodiment of the present disclosure,and FIG. 3 is a block diagram illustrating the refrigerator 100according to an embodiment of the present disclosure.

Referring to FIGS. 1, 2 and 3, the refrigerator 100 according to anembodiment of the present disclosure includes a main body 110 definingan external appearance of the refrigerator 100, a storage compartment120 in which food is stored, and a cooling unit 200 to cool the storagecompartment 120.

A duct (not shown), along which air cooled by the cooling unit 200moves, is defined in an empty wall space of the main body 110. A machineroom (not shown), in which some components of the cooling unit 200 areinstalled, is provided in a bottom region of the main body 110.

The storage compartment 120, in which food is stored, is defined insidethe main body 110.

The storage compartment 120 is divided into left and right storagecompartments with an intermediate partition interposed between thecompartments. Specifically, the storage compartment 120 includes arefrigerating compartment 121 in which food is kept at a temperatureslightly above freezing, and a freezing compartment 122 in which food iskept below a freezing temperature. The refrigerating compartment 121 andthe freezing compartment 122 have open fronts.

The respective storage compartments 120 are provided with temperaturesensing units 161 and 162 to sense temperatures of the storagecompartments 120. More specifically, the refrigerating compartment 121is provided with the first temperature sensing unit 161 that senses thetemperature of the refrigerating compartment 121 and outputs an electricsignal corresponding to the temperature of the refrigerating compartment121. The freezing compartment 122 is provided with the secondtemperature sensing unit 162 that senses the temperature of the freezingcompartment 122 and outputs an electric signal corresponding to thetemperature of the freezing compartment 122. The temperature sensingunits 161 and 162 may include a thermistor, for example, of which anelectric resistance changes with temperature.

The refrigerating compartment 121 and the freezing compartment 122having open front sides are shielded from an exterior environment by twodoors 131 and 132.

The doors 131 and 132 of the refrigerator 100 are provided with adisplay unit 290 that displays information regarding operation of therefrigerator 100 and a user interface panel (not shown) including aninput unit 280 that receives operation instructions input by a user.

The display unit 290 may include a Liquid Crystal Display (LCD) panel orOrganic Light Emitting Diode (OLED) panel. The display unit 290 displaysinformation regarding operation of the refrigerator 100, such as thetarget temperature and current temperature of the refrigeratingcompartment 121 and the target temperature and current temperature ofthe freezing compartment 122. In addition, the display unit 290 may beprovided with a speaker (not shown) to warn the user about abnormaloperation of the refrigerator 100.

The input unit 280 may include a button switch, a membrane switch, or atouchscreen switch, for example. The input unit 280 receives operationinstructions input by the user, such as power on/off of the refrigerator100, the target temperature of the refrigerating compartment 121, andthe target temperature of the freezing compartment 122, for example. Theinput unit 280 and the display unit 290 may be separate units, orembodied as a single integrated unit.

The cooling unit 200 includes a first cooling unit 201 to cool therefrigerating compartment 121 and a second cooling unit 202 to cool thefreezing compartment 122. The first and second cooling units 201 and 202respectively include compressors 211 and 212, condensers 221 and 222,expansion valves 231 and 232, and evaporators 241 and 242.

The compressors 211 and 212 are installed in the machine room (notshown) defined in the bottom region of the main body 110. Eachcompressor serves to compress low-pressure gas-phase refrigerant,evaporated by the evaporators 241 and 242 that will be describedhereinafter, to high-pressure gas-phase refrigerant using a rotationpower of a compressor motor that is rotated upon receiving electricpower from an external power source, and to pump the same to thecondensers 221 and 222.

The refrigerant may be circulated through the condensers 221 and 222,the expansion valves 231 and 232, and the evaporators 241 and 242 bypressure generated by the compressors 211 and 212. The compressors 211and 212 play the most important role in the cooling units 201 and 202 tocool the storage compartments 121 and 122.

The compressor motor (not shown) may include an induction AC servomotor, a synchronous AC servo motor, or a BrushLess Direct Current(BLDC) motor, for example.

The condensers 221 and 222 may be installed in the machine room (notshown) defined in the bottom region of the main body 110, or may beinstalled in the exterior of the main body 110, such as to a rearsurface of the refrigerator 100, for example.

The gas-phase refrigerant compressed by the compressors 211 and 212 iscondensed to liquid-phase refrigerant while passing through thecondensers 221 and 222. The refrigerant emits latent heat to thecondensers 221 and 222 during a condensation thereof. Latent heat of therefrigerant refers to thermal energy emitted outward from therefrigerant as gas-phase refrigerant cooled to a boiling point of therefrigerant is changed to liquid-phase refrigerant having the sametemperature, i.e. the boiling temperature. In addition, thermal energyabsorbed by the refrigerant as the liquid-phase refrigerant heated tothe boiling point of the refrigerant is changed to gas-phase refrigeranthaving the same temperature is also referred to as latent heat.

Because temperatures of the condensers 221 and 222 are raised by latentheat emitted from the refrigerant, additional radiation fans 151 and 152may be provided to cool the condensers 221 and 222 if the condensers 221and 222 are installed in the machine room (not shown).

The liquid-phase refrigerant condensed by the condensers 221 and 222 isdepressurized by the expansion values 231 and 232. Specifically, theexpansion valves 231 and 232 depressurize the high-pressure liquid-phaserefrigerant to a pressure at which the refrigerant is evaporable viathrottling action. The throttling action means that pressure of fluid isreduced without heat exchange with the outside as the fluid passesthrough a narrow path, such as a nozzle or orifice.

In addition, the expansion valves 231 and 232 may adjust an appropriateamount of the refrigerant to allow the refrigerant to absorb sufficientheat in the evaporators 241 and 242. For example, if the expansionvalves 231 and 232 are electronic valves, the opening ratio of theexpansion valves 231 and 232 may be adjusted in response to a controlsignal.

The evaporators 241 and 242 are arranged in the duct (not shown) that isdefined in the empty wall space of the main body 110 as described above.The evaporators 241 and 242 serve to evaporate the low-pressureliquid-phase refrigerant depressurized by the expansion valves 231 and232. The refrigerant absorbs latent heat from the evaporators 241 and242 during evaporation thereof. The evaporators 241 and 242, which aredeprived of thermal energy corresponding to latent heat of therefrigerant, and air around the evaporators 241 and 242 is cooled by theevaporators 241 and 242.

The low-pressure gas-phase refrigerant evaporated by the evaporators 241and 242 is returned to the compressors 211 and 212 to repeat therefrigeration cycle.

The cooling unit 200 may further include a defrosting heater (not shown)to remove frost from the evaporators 241 and 242. Sublimation of watervapor around the evaporators 241 and 242 occurring while the evaporators241 and 242 are cooled by the refrigerant or condensation of water vaporaround the evaporators 241 and 242 may cause frost to be formed on theevaporators 241 and 242. The front formed on the evaporators 241 and 242deteriorates heat-exchange efficiency of the evaporators 241 and 242,and consequently deteriorates a cooling efficiency of the refrigerator100. Therefore, the defrosting heater (not shown) may be provided toremove the front from the evaporators 241 and 242.

The refrigerator 100 according to an embodiment of the presentdisclosure is configured such that the cooling units 201 and 202respectively correspond to the refrigerating compartment 121 and thefreezing compartment 122. That is, the first cooling unit 201 to coolthe refrigerating compartment 121 includes a first compressor 211, afirst condenser 221, a first expansion valve 231, and a first evaporator241. The second cooling unit 202 to cool the freezing compartment 122includes a second compressor 212, a second condenser 222, a secondexpansion valve 232, and a second evaporator 242.

The first cooling unit 201 and the second cooling unit 202 are separatedfrom each other so as not to permit intermixing of the refrigerant, andare also spatially isolated from each other.

Cooling fans 141 and 142 realize air circulation through the duct (notshown) in the wall space of the main body 110 and the storagecompartment 120. Specifically, the cooling fans 141 and 142 expel aircooled by the evaporators 241 and 242 arranged in the duct (not shown)into the storage compartments 121 and 122.

The cooling fans 141 and 142 are respectively provided at therefrigerating compartment 121 and the freezing compartment 122.Specifically, the cooling fans include a first cooling fan 141 for aircirculation through the duct (not shown) provided at the refrigeratingcompartment 121 and the freezing compartment 122, and a second coolingfan 142 for air circulation through the duct (not shown) provided at thefreezing compartment 122 and the freezing compartment 122.

A drive unit 260 drives the compressors 211 and 212, the cooling fans141 and 142, and the radiation fans 151 and 152 in response to a controlsignal of a controller 250 that will be described hereinafter.

In particular, to drive the compressors 211 and 212, the drive unit 260may include a voltage source inverter. The voltage source inverterincludes a converter part to rectify commercial AC power to DC power, acondenser for DC link voltage smoothing, and an inverter part forsimultaneous control of rectified DC voltage and frequency in a PulseWidth Modulation (PWM) manner.

A storage unit 270 stores control programs and control data for controlof the operation of the refrigerator 100. Specifically, the storage unit270 may include a non-volatile memory (not shown) for permanent storageof control programs and control data, such as a magnetic disc, a solidstate disc, and the like, and a volatile memory (not shown) fortemporary storage of data generated in the course of controllingoperation of the refrigerator 100, such as a D-RAM, S-RAM, and the like.

The controller 250 controls an overall operation of the refrigerator100. Specifically, the controller 250 controls the drive unit 260 tocool the refrigerating compartment 121 or the freezing compartment 122based on a user instruction input via the input unit 280 and based onresults sensed by the temperature sensing units 161 and 162.

The configuration of the refrigerator 100 has been described above.Hereinafter, operation of the refrigerator 100 will be described.

Operation of the refrigerator 100 may be divided into an initialoperation mode, a normal operation mode, and an abnormal operation mode.

The initial operation mode refers to the case in which power isinitially applied to the refrigerator 100, or when the refrigerator 100is powered on. In the initial operation mode, the temperature of thestorage compartments 121 and 122 is a room temperature of 25° C., andthe cooling unit 200 is in an un-driven state.

The normal operation mode refers to the case in which the storagecompartments 121 and 122 are kept at a constant temperature. In thenormal operation mode, the temperature of the storage compartment 120 islowered as the cooling unit 200 is driven. That is, if the cooling unit200 is normally driven in a state in which the storage compartment 120is closed by the doors 131 and 132, this corresponds to the normaloperation mode.

The abnormal operation mode refers to the case in which the temperatureof the storage compartment 120 is continuously raised. In the abnormaloperation mode, lowering the temperature of the storage compartment 120may be impossible despite driving the cooling unit 200. For example, thecase in which the doors 131 and 132 of the storage compartments 121 and122 are opened, or the case in which heat exchange is not implementeddue to frost formed on the evaporators 241 and 242 corresponds to theabnormal operation mode.

The refrigerator 100 determines whether or not driving requirements, orconditions, of the cooling unit 200 are satisfied based on resultssensed by the temperature sensing units 161 and 162 provided in thestorage compartment 120. If the driving requirements of the cooling unit200 are satisfied, the refrigerator 100 drives the cooling unit 200 tocool the storage compartment 120. The driving requirements of thecooling unit 200 are conditions required to initiate driving the coolingunit 200 in order to keep the first storage compartment 121 and thesecond storage compartment 122 at predetermined target temperatures. Aswill be described hereinafter, the refrigerator 100 drives the coolingunit 200 to cool the storage compartment 120 when the temperature of thestorage compartment 120 reaches or exceeds an upper limit temperature.

For long-term storage of food, a primary function of the refrigerator100, a target temperature of the refrigerator 100 is predetermined. Thetarget temperature is initially set at the manufacturing stage of therefrigerator 100 and may be changed later via user manipulation.

For example, the refrigerating compartment 121, which keeps food at atemperature slightly above freezing, may have a target refrigeratingtemperature of approximately 4° C., and the freezing compartment 122,which keeps food below a freezing temperature, may have a targetfreezing temperature of approximately −20° C.

The refrigerator 100 sets the driving requirements to initiate drivingthe cooling unit 200 in order to keep the storage compartment 120 at thetarget temperature. In other words, when the temperature of the storagecompartment 120 reaches or exceeds a predetermined upper limittemperature, the refrigerator 100 drives the cooling unit 200 to coolthe storage compartment. Simultaneously, the refrigerator 100 setsdriving stop requirements to stop driving the cooling unit 200. In otherwords, when the temperature of the storage compartment 120 reaches orfalls below a predetermined lower limit temperature, the refrigerator100 stops driving the cooling unit 200 so as not to cool the storagecompartment. Here, the upper limit temperature may be set to be 1° C.higher than the target temperature, and the lower limit temperature maybe set to be 1° C. lower than the target temperature, for example.

For example, if the target refrigerating temperature of therefrigerating compartment 121 is 4° C., a refrigerating upper limittemperature may be 5° C. and a refrigerating lower limit temperature maybe 3° C. In addition, if the target freezing temperature of the freezingcompartment 122 is −20° C., a freezing upper limit temperature may be−19° C. and a freezing lower limit temperature may be −21° C. That is,the first compressor 211 included in the first cooling unit 201initiates driving thereof to cool the refrigerating compartment 121 whenthe temperature of the refrigerating compartment 121 reaches or exceeds5° C., and driving the first compressor 211 stops when the temperatureof the refrigerating compartment 121 reaches 3° C. In addition, thesecond compressor 212 included in the second cooling unit 202 initiatesdriving thereof to cool the freezing compartment 122 if the temperatureof the freezing compartment 122 reaches or exceeds −19° C., and drivingthe second compressor 212 stops if the temperature of the freezingcompartment 122 reaches −21° C.

As such, the refrigerator 100 controls driving the cooling unit 200based on the temperatures of the storage compartments 121 and 122. Inthis case, simultaneous driving the first cooling unit 201 and thesecond cooling unit 202, i.e. simultaneous driving the first compressor211 and the second compressor 212, may occur. If the first compressor211 and the second compressor 212 are simultaneously driven, however,the refrigerator 100 may suffer from a significant increase in noise andvibration, as well as excessive power consumption.

Accordingly, minimizing simultaneous driving the first compressor 211included in the first cooling unit 201 and the second compressor 212included in the second cooling unit 202 may be necessary. To this end,while any one of the first cooling unit 201 or the second cooling unit202 is being driven, the refrigerator 100 may delay driving the othercooling unit until delayed driving requirements of the other coolingunit are satisfied, even if driving the other cooling unit wouldnormally occur to lower a temperature. In other words, while any one ofthe first cooling unit 201 or the second cooling unit 202 is beingdriven, driving the other cooling unit is initiated only after the othercooling unit satisfies the delayed driving requirements. The delayeddriving requirements may include determining that a predetermined delaytime has passed, and that the temperature of the storage compartmentreaches a delay temperature higher than the upper limit temperature thatsatisfies the driving requirements.

Hereinafter, operation of the refrigerator 100 depending on eachoperation mode of the refrigerator 100 will be described.

First, operation of the refrigerator 100 in the initial operation modeof the refrigerator 100 will be described.

The refrigerator 100 determines the initial operation mode if thetemperatures of all the storage compartments 120 reach or exceed therespective upper limit temperatures in an un-driven state of all thecooling units 200, and then determines the end of the initial operationmode if the temperature of any one of the refrigerating compartment 121and the freezing compartment 122 reaches or falls below the lower limittemperature via driving the first cooling unit 201 or the second coolingunit 202. Of course, the disclosure is not limited to the abovedescription, and end of the initial operation mode may be determined ifthe temperatures of both the refrigerating compartment 121 and thefreezing compartment 122 fall below the respective lower limittemperatures.

If any one of the first cooling unit 201 or the second cooling unit 202is being driven in the initial operation mode of the refrigerator 100,the refrigerator 100 does not drive the other cooling unit for apredetermined delay time.

More specifically, when power is initially applied to the refrigerator100, both the first cooling unit 201 and the second cooling unit 202 arein an un-driven state and the temperatures of the refrigeratingcompartment 121 and the freezing compartment 122 are respectively higherthan the refrigerating upper limit temperature and the freezing upperlimit temperature. In this case, the refrigerator 100 may randomly driveany one of the first cooling unit 201 and the second cooling unit 202.If the second cooling unit 202 is first driven in the initial operationmode, the refrigerator 100 drives the first cooling unit 201 after apredetermined delay time has passed. The delay time may be set based onstorage capacity of the refrigerator 100, or cooling capacity of therefrigerator 100, for example.

The refrigerator 100 may drive the first cooling unit 201 when the delaytime has passed even during driving the second cooling unit 202. Thatis, the refrigerator 100 may not stop driving the second cooling unit202. In this case, both the first cooling unit 201 and the secondcooling unit 202 may be driven when the delay time has passed afterpower is initially applied to the refrigerator 100. In the case in whichthe first cooling unit 201 and the second cooling unit 202 are drivensimultaneously, the refrigerator 100 may reduce driving rates of thefirst compressor 211 and the second compressor 212 of the first coolingunit 201 and the second cooling unit 202. In other words, therefrigerator 100 may reduce noise and vibration caused by driving thecompressors 211 and 212, as well as power consumption of the compressors211 and 212, by reducing rates of rotation of the first compressor 211and the second compressor 212 (more accurately, rates of rotation of thecompressor motors (not shown) included in the first compressor 211 andthe second compressor 212).

Although the refrigerator 100 has been described as driving the firstcooling unit 201 and the second cooling unit 202 simultaneously when thedelay time has passed after power is initially applied to therefrigerator 100 and driving the second cooling unit 202 is initiated,the disclosure is not limited thereto, and the refrigerator 100 may stopdriving the second cooling unit 202 while continuously driving only thefirst cooling unit 201 when the delay time has passed after power isinitially applied to the refrigerator 100 and driving the second coolingunit 202 is initiated. That is, the first cooling unit 201 and thesecond cooling unit 202 may be alternately driven whenever the delaytime has passed.

Next, operation of the refrigerator 100 in the normal operation mode ofthe refrigerator 100 will be described.

When several minutes to several hours have passed after power isinitially applied to the refrigerator 100, the temperature of any one ofthe refrigerating compartment 121 and the freezing compartment 122reaches or falls below the lower limit temperature. In this case, therefrigerator 100 is in the normal operation mode. As described above, inthe normal operation mode, the temperature of the storage compartment120 is lowered as the refrigerator 100 drives the cooling unit 200.

In the normal operation mode, if any one of the first cooling unit 201or the second cooling unit 202 is being driven, the refrigerator 100does not drive the other cooling unit until the temperature of thestorage compartment that is cooled by the other cooling unit reaches thedelay temperature higher than the upper limit temperature. For example,if the first cooling unit 201 is being driven, the refrigerator 100drives the second cooling unit 202 only after the temperature of thefreezing compartment 122 reaches or exceeds a freezing delay temperaturethat is higher than the freezing upper limit temperature. In otherwords, while the first cooling unit 201 is being driven, the secondcooling unit 202 is not driven if the temperature of the freezingcompartment 122 is lower than the freezing delay temperature, even ifthe temperature of the freezing compartment 122 is higher than thefreezing upper limit temperature.

In addition, if the temperature of the storage compartment, which islowered via driving the first cooling unit 201 or the second coolingunit 202, reaches the lower limit temperature and thus driving thecorresponding cooling unit stops, the refrigerator 100 drives the othercooling unit. For example, in the case in which the first cooling unit201 is being driven and driving the second cooling unit 202 is delayed,the refrigerator 100 stops driving the first cooling unit 201 and drivesthe second cooling unit 202 if the temperature of the refrigeratingcompartment 121 reaches the refrigerating lower limit temperature evenbefore the temperature of the freezing compartment 122 reaches thefreezing delay temperature. Because driving the first cooling unit 201stops even if the temperature of the freezing compartment 122 is lessthan the freezing delay temperature, the refrigerator 100 may drive thesecond cooling unit 202 when the temperature of the freezing compartment122 reaches the freezing upper limit temperature.

If the refrigerator 100 delays driving any one of the cooling unitswhile the other cooling unit is being driven such that the temperatureof the storage compartment that is cooled by the delayed cooling unitreaches or exceeds the delay temperature, the refrigerator 100 may driveboth the cooling units. For example, if the temperature of the freezingcompartment 122 reaches the freezing delay temperature while the firstcooling unit 201 is being driven, the refrigerator 100 may drive boththe first cooling unit 201 and the second cooling unit 202. In the casein which both the first cooling unit 201 and the second cooling unit 202are driven, to reduce noise and vibration caused by driving the twocompressors 211 and 212, the refrigerator 100 may reduce rates ofrotation of the compressors 211 and 212 of the first cooling unit 201and the second cooling unit 202 (more accurately, rates of rotation ofthe compressor motors (not shown) included in the first compressor 211and the second compressor 212).

Moreover, if the refrigerator 100 delays driving any one of the coolingunits while the other cooling unit is being driven such that thetemperature of the storage compartment that is cooled by the delayedcooling unit reaches or exceeds the delay temperature, the refrigerator100 may stop the cooling unit that is being driven and drive the delayedcooling unit. For example, if the temperature of the freezingcompartment 122 reaches or exceeds the freezing delay temperature whilethe first cooling unit 201 is being driven, the refrigerator 100 maystop driving the first cooling unit 201 and drive the second coolingunit 202.

The delay temperature may be set based on storage capacity of therefrigerator 100, cooling capacity of the refrigerator 100, and thetarget temperature of the storage compartment 120, for example.

For example, the refrigerating delay temperature may be set to 7° C.,higher than the refrigerating upper limit temperature of 5° C., and thefreezing delay temperature may be set to −18° C., higher than thefreezing upper limit temperature of −19° C. That is, if the secondcooling unit 202 to cool the freezing compartment 122 is being driven,the first cooling unit 201 is not driven until the temperature of therefrigerating compartment 121 reaches the refrigerating delaytemperature of 7° C., which is higher than the refrigerating upper limittemperature of 5° C. Naturally, the first cooling unit 201 may be drivenif driving the second cooling unit 202 stops even before the temperatureof the refrigerating compartment 121 reaches 7° C. In addition, in thecase in which the first cooling unit 201 to cool the refrigeratingcompartment 121 is being driven, the second cooling unit 202 is notdriven until the temperature of the freezing compartment 122 reaches thefreezing delay temperature of −18° C., which is higher than the freezingupper limit temperature of −19° C. Naturally, the second cooling unit201 may be driven if driving the first cooling unit 201 stops evenbefore the temperature of the freezing compartment 122 reaches −18° C.

FIG. 4 is a view showing temperature variation of the first storagecompartment 121 and the second storage compartment 122 in the normaloperation mode of the refrigerator 100 according to an embodiment of thepresent disclosure.

Referring to FIG. 4, as the temperature of the freezing compartment 122reaches the freezing upper limit temperature of −19° C. at a time tafter the refrigerator 100 enters the normal operation mode, the secondcooling unit 202 is driven. Thereafter, even if the temperature of therefrigerating compartment 121 reaches the refrigerating upper limittemperature of 5° C. at a time t2, the first cooling unit 201 is notdriven because the second cooling unit 202 is being driven. Thereafter,when the temperature of the freezing compartment 122 reaches thefreezing lower limit temperature of −21° C. at a time t3, driving thesecond cooling unit 202 stops and the first cooling unit 201 is drivenbecause the temperature of the refrigerating compartment 121 is therefrigerating upper limit temperature of 5° C.

As shown in FIG. 4, in the normal operation mode, the refrigerator 100may minimize simultaneous driving the first cooling unit 201 and thesecond cooling unit 202.

Finally, the abnormal operation mode of the refrigerator 100 occurs inthe case in which any one or both of the two doors 131 and 132 used toclose the storage compartment 120 are opened, or occurs in the case inwhich the evaporators 241 and 242 of the cooling unit 200 do notimplement heat exchange. In the abnormal operation mode, the temperatureof the storage compartment 120 is not lowered despite driving thecooling unit 200.

If it is determined that the refrigerator 100 is in the abnormaloperation mode based on results sensed by the temperature sensing units161 and 162, the refrigerator 100 warns the user about the abnormaloperation of the refrigerator 100 via the speaker (not shown) providedat the display unit 290.

If abnormal operation is sensed in both the refrigerating compartment121 and the freezing compartment 122, that is, if it is determined thatboth the doors 131 and 132 of the refrigerator 100 are opened, therefrigerator 100 may alternately drive the first cooling unit 201 andthe second cooling unit 202 at a predetermined delay time interval.However, the disclosure is not limited thereto, and the refrigerator 100may drive both the first cooling unit 201 and the second cooling unit202. However, in the case in which both the first cooling unit 201 andthe second cooling unit 202 are driven, to reduce noise and vibrationcaused by driving the two compressors 211 and 212, the refrigerator 100may reduce rates of rotation of the compressors 211 and 212 of the firstcooling unit 201 and the second cooling unit 202 (more accurately, ratesof rotation of the compressor motors (not shown) included in the firstcompressor 211 and the second compressor 212).

If abnormal operation is sensed only in the refrigerating compartment121 and normal operation is sensed in the freezing compartment 122, thatis, if the temperature of the refrigerating compartment 121 is notlowered despite driving the first cooling unit 201, the refrigerator 100continuously drives the first cooling unit 201 in the normal operationmode of the second cooling unit 202. That is, through continuous drivingthe first cooling unit 201, the second cooling unit 202 is driven whenthe temperature of the freezing compartment reaches or exceeds thefreezing delay temperature, and stops driving when the temperature ofthe freezing compartment reaches or falls below the freezing lower limittemperature. In this case, both the first cooling unit 201 and thesecond cooling unit 202 may be driven simultaneously. In the case inwhich both the first cooling unit 201 and the second cooling unit 202are driven simultaneously, to reduce noise and vibration caused bydriving the two compressors 211 and 212, the refrigerator 100 may reducerates of rotation of the compressors 211 and 212 of the first coolingunit 201 and the second cooling unit 202 (more accurately, rates ofrotation of the compressor motors (not shown) included in the firstcompressor 211 and the second compressor 212).

In addition, the refrigerator 100 may drive the first cooling unit 201while the second cooling unit 202 is in an un-driven state in the normaloperation mode of the second cooling unit 202. In this case, it may bepossible to minimize simultaneous driving both the first cooling unit201 and the second cooling unit 202.

Hereinafter, operation of the refrigerator 100 will be described withreference to FIG. 4 that illustrates temperature variation of therefrigerating compartment 121 and the freezing compartment 122 caused byoperation of the refrigerator 100 according to an embodiment of thepresent disclosure. It is assumed that with the refrigeratingcompartment 121 has the refrigerating target temperature of 4° C., therefrigerating lower limit temperature of 3° C., the refrigerating upperlimit temperature of 5° C., and the refrigerating delay temperature of7° C., and the freezing compartment 122 has the freezing targettemperature of −20° C., the freezing lower limit temperature of −21° C.,the freezing upper limit temperature of −19° C., and the freezing delaytemperature of −18° C.

FIG. 5 is a flowchart illustrating a control method for the refrigeratoraccording to an embodiment of the present disclosure, FIG. 6 is aflowchart illustrating the control method in the initial operation modeof the refrigerator according to an embodiment of the presentdisclosure, and FIGS. 7 and 8 are flowcharts illustrating the controlmethod upon driving the first cooling unit and the second cooling unitof the refrigerator, respectively, according to an embodiment of thepresent disclosure.

Referring to FIG. 5, the refrigerator 100 first determines whether ornot the first cooling unit 201 is being driven (operation S310).

If the first cooling unit 201 is being driven (Yes of operation S310),the refrigerator 100 determines whether or not the temperature of thefreezing compartment 122 reaches or exceeds the freezing delaytemperature (operation S320).

If the temperature of the freezing compartment 122 is less than thefreezing delay temperature (No of operation S320), the refrigerator 100continuously determines whether or not the first cooling unit 201 isbeing driven and whether or not the temperature of the freezingcompartment 122 reaches or exceeds the freezing delay temperature untilthe first cooling unit 201 stops driving or the temperature of thefreezing compartment 122 reaches or exceeds the freezing delaytemperature.

If the temperature of the freezing compartment 122 reaches or exceedsthe freezing delay temperature (Yes of operation S320), the refrigerator100 drives the second cooling unit 202 (operation S330). In this case,after driving the second cooling unit 202 is initiated (operation S462),the refrigerator 100 determines whether or not the temperature of thefreezing compartment 122 is equal to or less than the freezing lowerlimit temperature (operation S464). If the temperature of the freezingcompartment 122 reaches or falls below the freezing lower limittemperature (Yes of operation S464), the refrigerator 100 stops drivingthe second cooling unit 202 (operation S466) (See FIG. 8).

If the first cooling unit 201 is in an un-driven state (No of operationS310), the refrigerator 100 determines whether or not the second coolingunit 202 is being driven (operation S340).

If the second cooling unit 202 is being driven (Yes of operation S340),the refrigerator 100 determines whether or not the temperature of therefrigerating compartment 121 reaches or exceeds the refrigerating delaytemperature (operation S350).

If the temperature of the refrigerating compartment 121 is less than therefrigerating delay temperature (No of operation S350), the refrigerator100 determines whether or not the second cooling unit 202 is beingdriven and whether or not the temperature of the refrigeratingcompartment 121 reaches or exceeds the refrigerating delay temperatureuntil the second cooling unit 202 stops driving or the temperature ofthe refrigerating compartment 121 reaches or exceeds the refrigeratingdelay temperature.

If the temperature of the refrigerating compartment 121 reaches orexceeds the refrigerating delay temperature (Yes of operation S350), therefrigerator 100 drives the first cooling unit 201 (operation S360). Inthis case, after driving the first cooling unit 201 is initiated(operation S452), the refrigerator 100 determines whether or not thetemperature of the refrigerating compartment 121 reaches or falls belowthe refrigerating lower limit temperature (operation S454). If thetemperature of the refrigerating compartment 121 reaches or falls belowthe refrigerating lower limit temperature (Yes of operation S454), therefrigerator 100 stops driving the first cooling unit 201 (operationS456) (See FIG. 7).

If the second cooling unit 202 is in an un-driven state, that is, ifboth the first cooling unit 201 and the second cooling unit 202 are inan un-driven state, the refrigerator 100 determines whether or not thetemperature of the refrigerating compartment 121 reaches or exceeds therefrigerating upper limit temperature (operation S370).

If the temperature of the refrigerating compartment 121 is less than therefrigerating upper limit temperature (No of operation S370), therefrigerator 100 determines whether or not the temperature of thefreezing compartment 122 reaches or exceeds the freezing upper limittemperature (operation S380).

If the temperature of the freezing compartment 122 reaches or exceedsthe freezing upper limit temperature (Yes of operation S380), therefrigerator 100 drives the second cooling unit 202 (operation S390). Inthis case, after driving the second cooling unit 202 is initiated(operation S462), the refrigerator 100 determines whether or not thetemperature of the freezing compartment 122 reaches or falls below thefreezing lower limit temperature (operation S464). If the temperature ofthe freezing compartment 122 reaches or falls below the freezing lowerlimit temperature (Yes of operation S464), the refrigerator 100 stopsdriving the second cooling unit 202 (operation S466) (See FIG. 8).

If the temperature of the freezing compartment 122 is less than thefreezing lower limit temperature (No of operation S380), that is, ifboth the first cooling unit 201 and the second cooling unit 202 are inan un-driven state and the temperatures of the freezing compartment 121and the freezing compartment 122 are less than the respective upperlimit temperatures, the refrigerator 100 determines whether or not thefirst cooling unit is being driven (operation S310).

If the temperature of the refrigerating compartment 121 reaches orexceeds the refrigerating upper limit temperature (Yes of operationS370), the refrigerator 100 determines whether or not the temperature ofthe freezing compartment 122 reaches or exceeds the freezing upper limittemperature (operation S400). If the temperature of the freezingcompartment 122 is less than the freezing upper limit temperature (No ofoperation S400), the refrigerator 100 drives the first cooling unit 201(operation S410). In this case, after driving the first cooling unit 201is initiated (operation S452), the refrigerator 100 determines whetheror not the temperature of the refrigerating compartment 121 reaches orfalls below the refrigerating lower limit temperature (operation S454).If the temperature of the refrigerating compartment 121 reaches or fallsbelow the refrigerating lower limit temperature, the refrigerator 100stops driving the first cooling unit 201 (operation S456) (See FIG. 7).

If the temperature of the freezing compartment 122 reaches or exceedsthe freezing upper limit temperature (Yes of operation S400), that is,if both the first cooling unit 201 and the second cooling unit 202 arein an un-driven state and the temperatures of the freezing compartment121 and the freezing compartment 122 reach or exceed the respectiveupper limit temperatures, the refrigerator 100 enters the initialoperation mode (operation S420).

If the refrigerator 100 enters the initial operation mode (operationS420), the refrigerator 100 drives the second cooling unit 202(operation S422), and determines whether or not a delay time has passedafter the second cooling unit 202 is driven (operation S424).

If the delay time has not passed (No of operation S424), therefrigerator 100 determines whether or not the second cooling unit 202is being driven (operation S426).

If the second cooling unit 202 is being driven (Yes of operation S426),the refrigerator 100 iteratively determines whether or not the delaytime has passed (operation S424).

If the second cooling unit 202 is in an un-driven state (No of operationS426), that is, if the temperature of the freezing compartment 122reaches the freezing lower limit temperature and the second cooling unit202 stops driving, the refrigerator 100 drives the first cooling unit201 (operation S428).

If the delay time has passed (Yes of operation S424), the refrigerator100 drives the first cooling unit 201 (operation S428).

As is apparent from the above description, according to an aspect of thepresent disclosure, it may be possible to minimize simultaneous drivinga plurality of compressors, which may prevent generation of noise andvibration, as well as excessive power consumption due to driving theplurality of compressors.

The above-described embodiments may be recorded in computer-readablemedia including program instructions to implement various operationsembodied by a computer. The media may also include, alone or incombination with the program instructions, data files, data structures,and the like. The program instructions recorded on the media may bethose specially designed and constructed for the purposes ofembodiments, or they may be of the kind well-known and available tothose having skill in the computer software arts. Examples ofcomputer-readable media include magnetic media such as hard disks,floppy disks, and magnetic tape; optical media such as CD ROM disks andDVDs; magneto-optical media such as optical disks; and hardware devicesthat are specially configured to store and perform program instructions,such as read-only memory (ROM), random access memory (RAM), flashmemory, and the like. The computer-readable media may also be adistributed network, so that the program instructions are stored andexecuted in a distributed fashion. The program instructions may beexecuted by one or more processors. The computer-readable media may alsobe embodied in at least one application specific integrated circuit(ASIC) or Field Programmable Gate Array (FPGA), which executes(processes like a processor) program instructions. Examples of programinstructions include both machine code, such as produced by a compiler,and files containing higher level code that may be executed by thecomputer using an interpreter. The above-described devices may beconfigured to act as one or more software modules in order to performthe operations of the above-described embodiments, or vice versa.

Although the embodiments of the present disclosure have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in the embodiment without departing from theprinciples and spirit of the disclosure, the scope of which is definedin the claims and their equivalents.

What is claimed is:
 1. A refrigerator comprising: a plurality of storagecompartments; a plurality of coolers configured to cool the plurality ofstorage compartments; a plurality of temperature sensors configured tosense temperatures of the plurality of storage compartments,respectively; a driver configured to drive the plurality of coolers; anda controller configured to control the driver to drive a first cooler ofthe plurality of coolers based on at least one sensed temperature of thesensed temperatures and a first temperature, wherein while a secondcooler of the plurality of coolers is being driven, the controller isconfigured to control the driver to drive the first cooler based on atleast one sensed temperature of the sensed temperatures and a secondtemperature being higher than the first temperature.
 2. The refrigeratoraccording to claim 1, wherein the controller is further configured toinitiate the driving of the first cooler based on a predetermined timeand a time for which the driving of the first cooler is delayed.
 3. Therefrigerator according to claim 2, wherein the controller is furtherconfigured to stop the driving of the second cooler in response to theinitiating of the driving of the first cooler.
 4. The refrigeratoraccording to claim 1, wherein the controller is further configured toreduce driving rates of the first cooler and the second cooler while thefirst cooler and the second cooler are driven simultaneously.
 5. Amethod for controlling a refrigerator including a plurality of storagecompartments, the method comprising: sensing temperatures of theplurality of storage compartments, respectively; cooling a first storagecompartment of the plurality of storage compartments based on at leastone sensed temperature of the sensed temperatures and a firsttemperature; and while a second storage compartment of the plurality ofstorage compartments is cooled, cooling the first storage compartment ofthe plurality of storage compartments based on at least one sensedtemperature of the sensed temperatures and a second temperature beinghigher than the first temperature.
 6. The method according to claim 5,further comprising initiating the cooling of the first storagecompartment based on a predetermined time and a time for which thecooling of the first storage compartment is delayed.
 7. The methodaccording to claim 6, further comprising stopping the cooling of thesecond storage compartment in response to the initiating the cooling ofthe first storage compartment.
 8. The method according to claim 5,further comprising reducing cooling rates of the first storagecompartment and the second storage compartment while the first storagecompartment and the second storage compartment are cooledsimultaneously.
 9. A refrigerator comprising: a plurality of storagecompartments; a plurality of coolers including a first cooler and asecond cooler and configured to cool the plurality of storagecompartments; a plurality of temperature sensors configured to sensetemperatures of the plurality of storage compartments, respectively; adriver configured to drive the plurality of cooling units; and acontroller configured to control the drive unit to drive the pluralityof coolers based on the sensed temperatures, wherein while the secondcooler is being driven, the controller is configured to delay drivingthe first cooler, and the controller is configured to initiate drivingthe first cooler in response to stopping the driving of the secondcooler.
 10. The refrigerator according to claim 9, wherein thecontroller is further configured to initiate the driving of the firstcooler based on a predetermined time and a time for which the driving ofthe first cooler is delayed.
 11. The refrigerator according to claim 9,wherein the controller is further configured to reduce driving rates ofthe first cooler and the second cooler while the first cooler and thesecond cooler are driven simultaneously.